Description of Business and Significant Accounting Policies (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 segment Item	Dec. 31, 2011	Dec. 31, 2010
Description of Business and Significant Accounting Policies
Length of interim quarter in fiscal year	91 days
Short-term Investments
Maturity period of short-term investments, minimum	3 months
Goodwill and Indefinite-Lived Intangibles
Number of reporting units	4
Trading days prior to measurement date	10 days
Number of reportable segments	2
Warranty Costs
Warranty period	1 year
Advertising Expense
Advertising expenses	$ 0.8	$ 1.4	$ 1.3
Negotiable Letters of Credit
Maturity period of irrevocable letters of credit, minimum	0 days
Maturity period of irrevocable letters of credit, maximum	90 days
Minimum
Definite-Lived Intangible and Long-Lived Assets
Estimated useful lives	2 years
Maximum
Definite-Lived Intangible and Long-Lived Assets
Estimated useful lives	17 years